Rf is equal to the distance traveled by the substance divided by the distance traveled by the solvent. Since the solvent used in the developing chamber was hexanes—a non-polar molecule— the more nonpolar the substance was, the stronger it would stick to the plate. This means that the more polar a pigment was, the higher it climbed on the TLC plate and would therefore have a larger Rf. There are 3 major classes of pigments present in spinach: carotenes, xanthophylls, and chlorophylls. Since the solvent is nonpolar, we would expect carotene to have the lowest Rf, then xanthophylls, and chlorophylls would have the highest.
Substrate concentration basically means the amount used for the substrate. The substrate in our experiment was 0.1% hydrogen peroxide. The 0.1% is the concentration amount. Just like temperature and pH, substrate concentration can speed the reaction only up to a certain limit. When we mixed pH 3 enzyme tube with substrate tube, we used 0.3 mL of hydrogen peroxide, but if we were to increase the amount, then the experiment would have been faster.
The reason for this is due to the alcohol functional group present in the salicylic acid starting material, as it has a higher Rf value when TLC is run on the compound in which it is contained at the start of the reaction. TLC of the Aspirin product contained an ester functional group, which was expected to have a lower Rf due to residual hydrogen bonding which occurred between the hydroxyl group of the carboxylic acid and adjacent carbonyl of the ester. Experimental results followed this expected outcome, indicating the successful synthesis of the experimental aspirin product, which maintained a lower Rf value than the reaction starting material (Rf Data Figure 1). Experimental IR results indicated the presence if characteristic wavelength peak values that are found in a successfully synthesized Acetylsalicylic Acid (2-acetoxybenzoic acid) or Aspirin product. The IR spectra revealed the presence of the ester functional group via a peak at 1760cm-1 indicating C=O carbonyl bonding of an ester.
However, the almost linear promoting effects of DME addition were found in propane and n-butane ignition delays [23, 25]. This is mainly due to that the reactivity of methane is much lower relative to that of DME. Therefore, even with a small amount of DME addition, the ignition was strongly promoted by the decomposition of DME accompanied by the rapid build-up of free radicals, thus lead to the nonlinear promoting effect on methane ignition [21, 22]. However, for the higher order alkanes such as propane and butane, the reactivity of which are higher and the ignition delay times are much shorter relative to methane. Moreover, in the high temperature oxidation of methane, the rate of the governing reaction CH4 + O2 CH3 + HO2 is much slower than of the similar reactions of the higher order alkanes .
The alkaline phosphatase has a lower enzymatic activity when pH 7 and 7.5 Tris-HCl were used; whereas the enzyme has a higher enzymatic activity when pH 8, 8.5 and 9 Tris-HCl were used, with the enzymatic activity at pH 9 being the highest. This shows that the alkaline phosphatase works optimally at alkaline condition such as pH 9 (Kaslow, n.d). The results of the graph show that alkaline phosphatase work less optimally at lower pH, this may due to at lower pH, the positively-charged amino side chain of the peptide sequence of alkaline phosphatase will release the hydrogen ions, therefore causing the tertiary structure of the enzyme altered, which will causes conformation change in alkaline phosphatase’s active site. Thus, the substrate p-nitrophenyl phosphate will experience some difficulties to bind to the binding site on active site of alkaline phosphatase, therefore decreasing the enzyme activity when pH becomes
8). The optimum ionic strength for red pigment production by M. purpureus was 1% NaCl. These results may be due to the increasing of electrolyte concentrations in saline environments tending to inhibit metabolic functions of the cells (Adler et al. 1982). The highest growth and red pigment production obtained from medium containing amino acid was L- tryptophan (4.75 ± 0.09 A500) and maximum dry cell mass was (3.9 ± 0.02 g/l) as shown in fig.
One progress on TLC called high performance TLC (HPTLC; Sherma and Jain, 2000).HPTLC makes use of gel qualities that are finer, so that thinner plates and smaller. This allows faster separation times and better separation efficiency. HPTLC has improved reduced resolution and detection limits, so that the to walk two dimensions. To phospholipids visible on the TLC plates are used detection reagents. spots corresponding phospholipids may be carbonized by the addition of phosphomolybdic acid, sulfuric acid or copper sulfate in phosphoric acid, and then heating of the sample.
The buoyancy lag time in simulated gastric fluid (0.1 mol L-1 HCL, pH 1.2) varied with the formulation variable. Formulation P1 exhibited the least buoyancy lag time (26 s) while formulation P6 exhibited the highest lag time (219 s). The decrease in the buoyancy lag time of a formulation P1 can be attributed to the availability of an increased amount of carbon dioxide as the with concentration of calcium carbonate which was entrapped in the formed gel to give rapid buoyancy. Irrespective of formulation variables, buoyancy duration was >12
The residual HA concentration of the settled water could be controlled within 1.50 mg/L. Meanwhile, the zeta potential of the coagulated HA generally increased with increasing CB dosage, indicating that the negative charges on the HA molecules was neutralized by the positive charges on the CB surface. This results are consistent with existing literature data for inorganic coagulants [4,25]. The number of charges on both HA and CB surfaces varied with pH , which might affect HA removal by coagulation. It was determined that as the solution pH decreased